DOI

10.5703/1288284313327

Abstract

The purpose of this study was to assess the behavior and durability of multi-span bridges constructed with full-span prestressed concrete form panels. The use of full-span prestressed concrete form panels for bridges with spans of 40 ft. or less is an economical method of construction due to the reduction of on-site formwork and labor required by alternate cast-in-place systems. In this research, a pair of two-span bridges utilizing full-span prestressed concrete form panels were fabricated and tested in the Karl H. Kettelhut Structural Engineering Laboratory at Purdue University. Time-dependent effects were monitored during the cast-in-place (CIP) concrete cure period of each bridge. At the conclusion of this period, each bridge was subjected to 5 million cycles of repeated service loading prior to a final loading to failure. In addition, one of the test bridges and five smaller composite specimens were exposed to a 15% sodium chloride solution followed by 3 days of drying at a minimum of 100o F. The durability of these bridges was then assessed by determining the potential for the build-up of chlorides at the boundary of the prestressed panels and CIP topping, and the resistance of the reinforcement to corrosion induced by chlorides. This study found that the PCA and CTL methods considerably overestimated the negative moments due to the restraint of time-dependent deformations in the laboratory test bridges. The negative restraint moments could be more accurately determined using a new method proposed in this report. The proposed method includes the effect of cracking of the CIP concrete at interior piers. This study also showed that adequate long-term performance could be achieved with bridges constructed using full-span precast prestressed concrete panels. The 5 million cycles of repeated service loading did not reduce the continuity between adjacent spans. Durability cycling revealed that an accumulation of chlorides at the boundary of the CIP topping and prestressed panels would not lead to a diminished load-carrying capacity of the structure. Sever corrosion occurred at the positive moment connection in the diaphragm of the test bridge. The connection detail should be modified before this construction method is implemented in the field.